Publications by authors named "Borovkova O"

We propose a magnetic photonic crystal (MPC) nanostructure with a gradient thickness of the magnetic layer. Such a nanostructure exhibits on-the-fly adjustment of optical and magneto-optical (MO) properties. Spatial displacement of the input beam allows tuning of the spectral position of the defect mode resonance in the bandgap of both transmission and magneto-optical spectra.

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Stability of platicons in hot cavities with normal group velocity dispersion at the interplay of Kerr and thermal nonlinearities was addressed numerically. The stability analysis was performed for different ranges of pump amplitude, thermal nonlinearity coefficient, and thermal relaxation time. It was revealed that for the positive thermal effect (i.

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For the first time, to the best of our knowledge, the properties of the Faraday effect are addressed in a magnetoplasmonic nanostructure with nonuniform spatial distribution of the magnetization. It is shown that the coincidence in period and phase between magnetization modulation and the field of the optical mode provides the resonant enhancement of the Faraday effect. This effect is observed for both the surface plasmon polariton and waveguide modes.

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A method of spectrally selective detection of short spin waves (or magnons) by means of the transverse magneto-optical (MO) intensity effect in transmission in the magnetoplasmonic nanostructure is proposed. We considered the spin waves with a wavelength equal to or less than (by an integer number of times) the period of the plasmonic structure, that is, of the order of hundreds of nanometers or 1-2 μm. The method is based on the analysis of the MO effect spectrum versus the modulation of the sample magnetization (created by the spin wave) and related spatial symmetry breaking in the magnetic layer.

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We propose a novel, to the best of our knowledge, technique for magnetoplasmonic nanostructures fabrication based on the pulse force nanolithography method. It allows one to create the high-quality magnetoplasmonic nanostructures that have lower total losses than the gratings made by the electron-beam lithography. The method provides control of the surface plasmon polaritons excitation efficiency by varying the grating parameters such as the scratching depth or the number of scratches in a single period.

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Here we propose a magnetophotonic structure for the layer-selective magnetization switching with femtosecond laser pulses of different wavelengths. It is based on a chirped magnetophotonic crystal (MPC) containing magnetic GdFeCo and nonmagnetic dielectric layers. At each operating wavelength the laser pulses heat up to necessary level only one GdFeCo layer that leads to its magnetization reversal without any impact on the magnetization of the other layers.

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We propose a novel method to enhance the transverse magneto-optical Kerr effect (TMOKE) in the magneto-plasmonic (MP) nanostructures by means of the active dielectric layer. We report the theoretical analysis of the MP structure with a ferromagnetic dielectric doped with rear-earth ions (Nd) as the example of a gain layer. The enhancement takes place near the surface plasmon polariton (SPP) resonances of the nanostructures.

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The homogeneous nucleation of bismuth supersaturated vapor is studied in a laminar flow quartz tube nucleation chamber. The concentration, size, and morphology of outcoming aerosol particles are analyzed by a transmission electron microscope (TEM) and an automatic diffusion battery (ADB). The wall deposit morphology is studied by scanning electron microscopy.

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We predict that a photonic crystal fiber whose strands are filled with a defocusing nonlinear medium can support stable bright solitons and also vortex solitons if the strength of the defocusing nonlinearity grows toward the periphery of the fiber. The domains of soliton existence depend on the transverse growth rate of the filling nonlinearity and nonlinearity of the core. Remarkably, solitons exist even when the core material is linear.

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We uncover that, in contrast to the common belief, stable dissipative solitons exist in media with uniform gain in the presence of nonuniform cubic losses, whose local strength grows with coordinate η (in one dimension) faster than |η|. The spatially-inhomogeneous absorption also supports new types of solitons, that do not exist in uniform dissipative media. In particular, single-well absorption profiles give rise to spontaneous symmetry breaking of fundamental solitons in the presence of uniform focusing nonlinearity, while stable dipoles are supported by double-well absorption landscapes.

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We report that defocusing cubic media with spatially inhomogeneous nonlinearity, whose strength increases rapidly enough toward the periphery, can support stable bright localized modes. Such nonlinearity landscapes give rise to a variety of stable solitons in all three dimensions, including one-dimensional fundamental and multihump states, two-dimensional vortex solitons with arbitrarily high topological charges, and fundamental solitons in three dimensions. Solitons maintain their coherence in the state of motion, oscillating in the nonlinear potential as robust quasiparticles and colliding elastically.

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We address the properties of multivortex soliton complexes supported by multiring gain landscapes in focusing Kerr nonlinear media with strong two-photon absorption. Stable complexes incorporating two, three, or four vortices featuring opposite or identical topological charges are shown to exist. In the simplest geometries with two amplifying rings vortex twins with equal topological charges exhibit asymmetric intensity distributions, while vortex anti-twins may be symmetric or asymmetric, depending on the gain level and separation between rings.

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We demonstrate that spatially inhomogeneous defocusing nonlinear landscapes with the nonlinearity coefficient growing toward the periphery as (1+|r|(α)) support one- and two-dimensional fundamental and higher-order bright solitons, as well as vortex solitons, with algebraically decaying tails. The energy flow of the solitons converges as long as nonlinearity growth rate exceeds the dimensionality, i.e.

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We introduce a general approach for generation of sets of three-dimensional quasi-nonspreading wave packets propagating in linear media, also referred to as linear light bullets. The spectrum of rigorously nonspreading wave packets in media with anomalous group velocity dispersion is localized on the surface of a sphere, thus drastically restricting the possible wave packet shapes. However, broadening slightly the spectrum affords the generation of a large variety of quasi-nonspreading distributions featuring complex topologies and shapes in space and time that are of interest in different areas, such as biophysics or nanosurgery.

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We show that ringlike localized gain landscapes imprinted in focusing cubic (Kerr) nonlinear media with strong two-photon absorption support new types of stable higher-order vortex solitons containing multiple phase singularities nested inside a single core. The phase singularities are found to rotate around the center of the gain landscape, with the rotation period being determined by the strength of the gain and the nonlinear absorption.

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Background: Aerosol lung administration is a convenient way to deliver water-insoluble or poorly soluble drugs, provided that small-sized particles are generated. Here, for the outbred male mice, we show that the pulmonary administration of ibuprofen nanoparticles requires a dose that is three to five orders of magnitude less than that for the orally delivered particles at the same analgesic effect.

Method: The aerosol evaporation-condensation generator consisted of a horizontal cylindrical quartz tube with an outer heater.

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The changes in the activity of cell nuclear sphingomyelinase at different times of activation of RNA and DNA syntheses in regenerating rat liver were studied. A comparative analysis of the intranuclear content of sphingomyelin and the primary product of the sphingomyelinase reaction, ceramide, as well as of other classes of phospholipids and neutral lipids, was carried out. The changes in the sphingomyelin and ceramide content in the nuclei during the induction of synthetic processes were more conspicuous as compared with other phospholipid classes.

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Using a model of cycloheximide (CHI)-induced expression of nuclear oncogens, a comparative study of metabolism of the major lipid classes in rat liver nuclei and cells was carried out. A short-term activation of sphingomyelinase which preceded on a time scale the maximal accumulation of c-fos and c-myc transcripts was observed both in the cells and in the nuclei. In contrast with the whole cell, the level of phospholipase C activity in the nuclei did not change under conditions of oncogene activation.

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